1. Field of the Invention
The present invention relates to a valve operating apparatus for an internal combustion engine and, more specifically, to an apparatus to cause the engine valve to operate or not to operate depending on the energization state of a solenoid actuator.
2. Description of the Prior Art
Variable valve control systems for multiple valve engines wherein the intake and/or exhaust valves can either be selectively actuated or actuated at selected lift profiles, are well known in the art. Example systems are shown in U.S. Pat. Nos. 4,151,817 and 4,203,397 the disclosures of which are hereby incorporated by reference except those portions which also incorporate by reference. U.S. Pat. No. 4,151,817 discloses a primary rocker arm element engageable with a first cam profile, a secondary rocker arm element engageable with a second cam profile, and means to interconnect or latch the primary and secondary arm elements. U.S. Pat. No. 4,203,397 discloses an apparatus to selectively engage or disengage an engine poppet valve so as to connect or disconnect the valve from the rest of the valve gear using a latch mechanism thereby causing the valve to operate or remain stationary.
Latchable rocker arm mechanisms known in the prior art do not provide for a relatively low activation force when the mechanism is to be shifted from either an active state to an inactive state or visa versa. Solenoid actuators, when used with the prior art mechanisms, provide a high force level in order to effectuate the actuation of the latchable rocker arm with some type of motion amplification mechanism such as a bellcrank. It would be desirable, especially for packaging, to provide a latchable rocker arm that requires a low level of solenoid force to effectuate a shift of an engine valve from an active to an inactive state and visa versa without the need for a synchronization system for timing with the rotation of the engine.